1. Field of the Invention
The present invention relates to a data processor system mainly used for controlling processes on an on-line basis, and more particularly, it relates to a stored-program type data processor capable of performing the duplex functions of operational processing (for example, scientific computation, edition, computer language compiling, etc.) inherent in standard computers and high response sequence controlling operations inherent in sequencers.
2. Description of the Prior Art
Today, interconnections of relay coils and contacts constitute, on the one hand, the most popular arrangement for performing desired sequence control and, on the other hand, various programmable sequence controllers are being contrived which are widely applicable to objects to be controlled, including processes and apparatuses. Among programmable sequence controllers, those suitable for carrying out complicated and high grade sequence control operations are called stored-program type sequencers. A stored-program type sequencer is provided with an addressed input unit for fetching input signals from an object to be controlled (for example, from limit switches and switches related thereto), an addressed output unit for sending output signals to the object to be controlled (for example, to solenoid valves and motor contactors) and a memory for storing a program edited on the basis of these addresses, and it sequentially reads the stored program out of the memory to produce a sequence controlling output.
The common stored-program type sequencer, as described above, however, is subject to the difficult problem that such a sequencer can only operate to carry out a digital sequence of processing controls concerning on-off signals generated by contacts. In many applications, the process to be controlled includes not only digital sequence control but also coexistent analog signals. Therefore, there is the need for use of an analog input-output units with such a sequencer as well as an analog to digital data processing converter. Conventionally, a sequencer and a computer were alternately used in accordance with a variety of process operations for controlling the process including coexistent analog signals. However, the disadvantages in such use of both a sequencer and a computer for a single process are obvious.